Female trees, such as crabapple trees and ginkgoes, are disliked in many cities because of the mess they leave in late summer.

“The female ginkgoes drop their fruit, which smells bad, and the ornamental crabapples drop these little rotten apples,” says McGrath, who explains that many of the female trees are killed due to their unpleasant odor.

With a smaller female tree population, areas are seeing more male trees, which are responsible for producing allergy-causing pollen.

“So, not only are there more trees producing pollen than there used to be because there isn’t the mix, but we honestly think that the men are frustrated and they just keep shooting it into the air all season long,” says McGrath. “These male trees would suffer great unrequited love and spend the entire spring just pumping out pounds and pounds of pollen.”